Absorbent article

ABSTRACT

An absorbent article includes an absorber having a front surface side sheet, a back surface side sheet disposed on the back surface side of the front surface side sheet, cells each of which is surrounded by bonded portions of the front surface side sheet and the back surface side sheet and inside each of which the front surface side sheet and the back surface side sheet are not bonded, and particulate materials which include superabsorbent polymer particles and which are contained in each of the cells. The bonded portions are arranged in continuous line shapes or dotted line shapes so as to form same-sized regular hexagons, which connect each other as unit shapes to be a honeycomb shape. All the cells are the same-sized regular hexagonal cells each of which is surrounded by the bonded portions.

TECHNICAL FIELD

The present invention relates to an absorbent article such as adisposable diaper and a sanitary napkin.

BACKGROUND ART

The absorbent article includes an absorber and a liquid-pervious topsheet covering the front surface side of the absorber. Excretion liquidsuch as urine and menstrual blood passes through the top sheet and isabsorbed and held by the absorber. An absorber obtained by mixingsuperabsorbent polymer (SAP) particles with hydrophilic short fiberssuch as fluff pulp and being accumulated in a cotton form has beenwidely used. However, in response to the request for further thinning,weight reduction, and cost reduction while ensuring a sufficientabsorbable amount, various types of absorbers (hereinafter also referredto as cell absorbers) are proposed. Such an absorber includes a largenumber of cells (small chambers), which are surrounded by bondedportions of the front surface side sheet and the back surface side sheetand in each of which the front surface side sheet and the back surfaceside sheet are not bonded, and particulate materials includingsuperabsorbent polymer particles are contained in the cells (forexample, refer to Patent Literatures 1 to 8 below).

In such a cell absorber, when the volume of the superabsorbent polymerparticles in the state of saturated absorption in each cell issufficiently larger than the volume of the cell, the superabsorbentpolymer particles fill in the cell upon the absorption, and there is apossibility that the absorption amount and absorption rate are lowereddue to inhibition by the swelling and so-called gel blocking, thecomfort in wearing may be deteriorated since the cell becomes hard dueto the swelling pressure of the superabsorbent polymer particles, andthe superabsorbent polymer particles may leak from gaps among fibers inthe case where the front surface side sheet and the back surface sidesheet are nonwoven fabrics.

For this reason, in the cell absorber, a structure is proposed in whichthe bonded portions of the front surface side sheet and the back surfaceside sheet are peeled off during absorption, and the volume of each cellis enlarged by coalescence of adjacent cells (for example, refer toPatent Ligatures 1 to 5 below).

However, the conventional cell absorber has room for improvement interms of ease of coalescence of the adjacent cells (that is, ease ofpeeling off of the bonded portions between the adjacent cells) andincrease in the volume of the cell relative to the number of coalescedcells.

CITATION LIST Patent Literature

Patent Literature 1: JP 2009-061230 A

Patent Literature 2: JP 09-504207 A

Patent Literature 3: JP 2014-500736 A

Patent Literature 4: Registered Utility Model No. 03172565

Patent Literature 5: JP 2011-189067 A

Patent Literature 6: JP 09-327479 A

Patent Literature 7: JP 10-137291 A

Patent Literature 8: JP 2003-265525 A

SUMMARY OF INVENTION Technical Problem

Therefore, an object of the present invention is to provide an absorbentarticle having a cell absorber in which adjacent cells can be easilycoalesced and which is excellent in the amount of increase in the volumeof the cell with respect to the number of coalesced cells.

Solution to Problem

Representative aspects of the present invention that solve the aboveproblems are as follows.

First Aspect

An absorbent article comprising an absorber including:

a front surface side sheet;

a back surface side sheet disposed on the back surface side of the frontsurface side sheet;

a plurality of cells each of which is surrounded by bonded portions ofthe front surface side sheet and the back surface side sheet, and insideeach of which the front surface side sheet and the back surface sidesheet are not bonded; and

particulate materials which include superabsorbent polymer particles andwhich are contained in the cells,

wherein the bonded portions are provided in continuous line shapes ordotted line shapes so as to form a honeycomb shape having the same-sizedregular hexagons as unit shapes,

all the cells are the same-sized regular hexagonal cells each of whichis surrounded by the bonded portions, and

the bonded portions positioned on at least one side of each cell areweak bonded portions which can be peeled off due to a swelling force ofthe superabsorbent polymer particles in the cells adjacent to the bondedportions.

Function and Effect

Comparing with other shapes with the same area, the perimeter of aregular hexagonal cell is the shortest. Accordingly, in the case wherethe bonded portions surrounding the cell are weak bonded portions whichcan be peeled off, when the planar shape of the cell is a regularhexagon, the weak bonded portions can be peeled off with low swellingforce. Therefore, in the case where the bonded portions surrounding thecell are weak bonded portions which can be peeled off, when all thecells are formed into the same sized regular hexagons by forming thebonded portion into a honeycomb shape, the adjacent cells are moresmoothly and quickly coalesced upon the absorption. Further, if theplanar shape of the cell is a regular hexagon, the increase in thevolume of the cell relative to the number of the coalesced cells is alsoexcellent. Therefore, it is possible to efficiently increase in thevolume of the cell due to the coalescence of the cell.

As is apparent from the above-described restriction that “having thesame-sized regular hexagons as unit shapes”, the term “honeycomb” in thepresent invention does not include a honeycomb in which planarly filledunit hexagons are not regular hexagons. In addition, a regular hexagonmay be elastically deformed from an original regular hexagon, which iscaused by the stretching and contracting of the front surface side sheetand the back surface side sheet in the manufacturing. However, the term“regular hexagon” includes such a deformed hexagon as long as the rateof the deformation is within ±5% in the front-back direction.

Second Aspect

The absorbent article according to the first aspect, comprising aplurality of the maximum enlargement sections in each of which a portioncomposed of six or more cells aligned in two or more directions issurrounded by strong bonded portions which are not peeled off againstthe swelling force of the superabsorbent polymer particles in theadjacent cells,

wherein the bonded portions positioned inside the strong bonded portionsin the maximum enlargement sections, are the weak bonded portions, and

peripheral edge shapes of the maximum enlargement sections are closedshapes formed by connecting two to four continuous sides per each cellin cells along the peripheral edges of the maximum enlargement sections.

Function and Effect

If the bonded portions are uniformly peeled off almost entirely exceptfor the peripheral edge of the cell absorber as in the conventionalcases, the gelled superabsorbent polymer particles swollen upon theabsorption move and collect to a low place such as a crotch portion, andthe comfort in wearing may be deteriorated.

On the contrary, as described in Patent Literature 3, it is effectivethat a large number of strong bonded portions which are not peeled offupon the absorption and a large number of weak bonded portions which arepeeled off upon the absorption are combined, the weak bonded portionsare provided at intervals in maximum enlargement sections surrounded bythe strong bonded portions, respectively and superabsorbent polymerparticles are arranged in the cells surrounded by these bonded portions,respectively. However, as illustrated in FIG. 5 of Patent Literature 3,if the maximum enlargement section surrounded by the strong bondedportions is too small, it becomes insignificant to provide the strongbonded portions, and as illustrated in FIG. 14, when the maximumenlargement section is formed to be elongated, after the cells arecoalesced, the maximum enlargement section becomes to have a shape inwhich it is difficult for the cells to be swollen.

On the contrary, when the strong bonded portions surround the portioncomposed of six or more regular hexagonal cells arranged in two or moredirections to form the maximum enlargement section having a closed shapeformed by connecting two to four continuous sides per each cell in thecells, the cells can be successively coalesced and smoothly enlarged tothe maximum enlargement section, the maximum enlargement section becomesto be swollen easily, and the increase in the volume of the cell withrespect to the number of the coalesced cells is excellent when the cellsare enlarged to the maximum enlargement section.

Third Aspect

The absorbent article according to the first or second aspect,

wherein longitudinal-strong-bond lines on which the strong bondedportions are continuously provided in the front-back direction along themaximum length of the absorber, are provided in the center portion andthe both side portions in the width direction of the absorber,respectively,

a plurality of lateral-strong-bond lines on which the strong bondedportions are provided continuously in the width direction or the obliquedirection from the longitudinal-strong-bond line in the center portionto each of the longitudinal-strong-bond lines in the both side portionsis provided at intervals in the front-back direction, and

sections, which are surrounded by the longitudinal-strong-bond lines andthe lateral-strong-bond lines so as to be partitioned, are the maximumenlargement sections in which the bonded portions positioned betweencells in the sections are only the weak bonded portions.

Function and Effect

The strong bonded portions are not peeled off even if the cells on theboth sides thereof are swollen upon the absorption, and a groove havingthe strong bonded portions as the bottom is formed after the absorption.Therefore, the liquid diffusibility in the direction along the grooveimproves. Therefore, in the case of this aspect, the liquiddiffusibility in the longitudinal direction is improved by thelongitudinal-strong-bond lines in each of which the strong bondedportions are continuously arranged in the front-back direction, and theliquid diffusibility in the lateral direction is improved by thelateral-strong-bond lines in each of which the strong bonded portionsare continuously arranged in the width direction or oblique direction.In addition, the longitudinal-strong-bond lines in the both sideportions also have a function of preventing leakage of thesuperabsorbent polymer particles from the both side edges.

Fourth Aspect

The absorbent article according to the third aspect,

wherein the lateral-strong-bond lines are formed in a zigzag shapeextending in the front-back direction while repeatedly bending left andright between the longitudinal-strong-bond line in the center portionand each of the longitudinal-strong-bond lines in the both sideportions.

Function and Effect

When the lateral-strong-bond lines are formed in a zigzag shape asdescribed above, it is preferable, because liquid diffusion in thelateral direction can be efficiently facilitated with the small numberof the lateral-strong-bond lines, each maximum enlargement section has asubstantially triangular shape which is easily swollen, and the increasein the volume of the cell relative to the number of coalesced cells isexcellent.

Fifth Aspect

The absorbent article according to any one of the first to fourthaspects,

wherein the bonded portions are arranged such that the parallel oppositesides of the regular hexagons formed in the honeycomb-shaped bondedportions are along the width direction,

at least one low-swelling-cell row in which all of the bonded portionson the both side edges thereof aligned linearly in the front-backdirection are the strong bonded portions is provided in the center inthe width direction of the absorber, and the both sides in the widthdirection of the low-swelling-cell row, have a higher swellable heightthan the low-swelling-cell row.

Function and Effect

The low-swelling-cell row is a row in which both side edges comprised ofthe strong bonded portions are aligned linearly in the front-backdirection and the maximum volume of each cell is small, and the heightcan be kept low even if the inside superabsorbent polymer particles areswollen. When the portions having a higher swellable height than thelow-swelling-cell row are provided on the both sides in the widthdirection of the low-swelling-cell row, a groove having thelow-swelling-cell row as the bottom is formed after the absorption, andtherefore the liquid diffusibility in the front-back direction along thegroove improves.

Sixth Aspect

The absorbent article according to the fifth aspect,

wherein the low-swelling-cell row does not contain a superabsorbentpolymer particle or contains a smaller amount of the superabsorbentpolymer particles per unit area than the cells on the both sides in thewidth direction of the low-swelling-cell row.

Function and Effect

By reducing the amount of the contained superabsorbent polymer particlesin this manner, it is possible to form a liquid diffusion groove havinga low bottom even upon the absorption. In addition, the inside of thelow-swelling-cell row does not give a hard texture due to the swellingpressure upon the absorption.

Seventh Aspect

The absorbent article according to the second aspect,

wherein the bonded portions are portions at which the front surface sidesheet and the back surface side sheet are welded,

the weak bonded portions and the strong bonded portions are provided indotted line patterns,

the line width of the weak bonded portions is narrower than the linewidth of the strong bonded portions, and

the point interval of the weak bonded portions is wider than the pointinterval of the strong bonded portions.

Function and Effect

In the case of forming the bonded portions by welding the front surfaceside sheet and the back surface side sheet, the weak bonded portions canbe formed only by forming the bonded portions into a dotted line shapeand widening the point interval. However, since the bonded portionsfunction as a boundary between each pair of the adjacent cells, if thepoint interval becomes too large, the gaps are increased in the boundarybetween each pair of the adjacent cells, which causes the superabsorbentpolymer particles to move easily. Therefore, when the weak bondedportions are formed into the dotted line shape by combining andarranging the width of the line width of the bonded portions and thewidth of the interval of each pair of the adjacent bonded portions, theweak bonded portions are likely to be peeled off in spite of the narrowgaps.

Eighth Aspect

The absorbent article according to any one of the first to seventhaspects,

wherein the bonded portion is not provided at positions where the sideson which the weak bonded portions are positioned intersect with eachother in the cells.

Function and Effect

If the bonded portion is not provided at the position where the sides onwhich the weak bonded portions are positioned intersect with each other,it is preferable since the weak bonded portions are likely to be peeledoff, and the cells are coalesced smoothly.

Ninth Aspect

The absorbent article according to any one of the first to eighthaspects,

wherein at least cells arranged at positions through which the front andback ends of the absorber pass and cells in the both side portions in anintermediate portion of the front-back direction of the absorber areempty cells which do not contain a superabsorbent polymer particle orwhich contains a smaller amount of the superabsorbent polymer particlesper unit area than other cells.

Function and Effect

For example, since the front end and the back end of the absorber areformed by cutting into individual absorbers in the manufacturing, if thesuperabsorbent polymer particles are included in the front end and theback end of the absorber, the life of a blade of a cutting device may beshortened. Therefore, it is desirable that the cells at the positionsthrough which the front and back ends of the absorber pass be emptycells. Further, in an absorber obtained by mixing the superabsorbentpolymer particles with hydrophilic short fibers such as fluff pulp andaccumulating them in a cotton form, generally the intermediate portionof the absorber in the front-back direction LD is formed in a shapenarrowing along the legs. However, even in the cell absorber, by settingthe cells on the both side portions in the intermediate portion in thefront-back direction as empty cells, this portion is less swollen evenafter absorption, and therefore, the absorber fits around the legs evenafter the absorption.

Advantage Effects of Invention

The present invention provides an advantage that an absorbent articlehaving a cell absorber in which adjacent cells can be easily coalescedand which is excellent in the increase in the volume of the cell withrespect to the number of coalesced cells.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view illustrating the inner surface of a tape-typedisposable diaper in a state where a diaper is spread.

FIG. 2 is a plan view illustrating the external surface of a tape-typedisposable diaper in a state where a diaper is spread.

FIG. 3 is a cross-sectional view taken along line 6-6 in FIG. 1.

FIG. 4 is a cross-sectional view taken along line 7-7 in FIG. 1.

FIG. 5(a) is a cross-sectional view taken along line 8-8 in FIG. 1, andFIG. 5(b) is a cross-sectional view taken along line 9-9 in FIG. 1.

FIG. 6 is a cross-sectional view taken along line 5-5 in FIG. 1.

FIG. 7(a) is a fragmentary plan view of a main part of an absorber, andFIG. 7(b) is a cross-sectional view taken along line 1-1 of FIG. 7(a).

FIG. 8 is a plan view of an absorber.

FIG. 9 is a plan view of an absorber.

FIG. 10 is cross-sectional views taken along line 2-2 in FIGS. 8 and 9.

FIG. 11 is a plan view of an absorber illustrating bonded portionssimilar to FIG. 8 in a simplified manner.

FIG. 12 is a plan view of an absorber illustrating bonded portions in asimplified manner.

FIG. 13 is a plan view of an absorber illustrating bonded portions in asimplified manner.

FIG. 14 is a plan view of an absorber illustrating bonded portions in asimplified manner.

FIG. 15 is a plan view of an absorber illustrating bonded portions in asimplified manner.

FIG. 16 is a plan view of an absorber illustrating bonded portions in asimplified manner.

FIG. 17 is a cross-sectional view taken along line 3-3 of FIG. 15.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to the accompanying drawings.

<Example of Absorbent Article>

FIGS. 1 to 6 illustrate examples of a tape-type disposable diaper, inwhich the reference sign X indicates the maximum width of the diaperexcluding a fastening tape, and the reference sign L indicates themaximum length of the diaper. Each component member is fixed or bondedin the same manner as known diapers as necessary except for the fixingor bonded portion described below. As a unit for fixing or bonding, ahot melt adhesive or welding (heat welding, ultrasonic welding) can beselected as appropriate.

This tape type disposable diaper has a basic structure in which anabsorber 50 is interposed between a liquid pervious top sheet and aliquid impervious sheet positioned on the external surface side. Thetape type disposable diaper includes a ventral side end flap portion EF,a dorsal side end flap portion EF, and a pair of side flap portions SF.The ventral side end flap portion EF and the dorsal side end flapportion EF are portions extending to the front side and the back side ofthe absorber 50 respectively and do not include the absorber 50. Thepair of the side flap portions SF extends laterally from the side edgesof the absorber 50. In each of the side flap portions SF in a dorsalside portion B, a fastening tape 13 is provided. When a user wears thediaper, the fastening tape 13 is engaged at an appropriate place on theexternal surface of the ventral side portion F in a state in which theside flap portion SF of the dorsal side portion B is overlaid on theexternal side of the side flap portion SF of the ventral side portion F.

In this tape type disposable diaper, the entire external surface of theabsorbent main unit 10 and the side flap portions SF is formed by anouter sheet 12. Particularly, in a region including the absorber 50, aliquid impervious sheet 11 is fixed to the internal surface side of theouter sheet 12 with an adhesive such as a hot melt adhesive. Further,the absorber 50, an intermediate sheet 40, and a top sheet 30 arestacked in this order on the internal surface side of the liquidimpervious sheet 11. In the illustrated example, the top sheet 30 andthe liquid impervious sheet 11 are rectangular in shape and havesomewhat larger sizes in the front-back direction LD and the widthdirection WD than the absorber 50. The peripheral edge portionprotruding from the side edges of the absorber 50 in the top sheet 30and the peripheral edge portion protruding from the side edges of theabsorber 50 in the liquid impervious sheet 11 are bonded by a hot meltadhesive or the like. Further, the liquid impervious sheet 11 is formedto be slightly wider than the top sheet 30.

On both sides of the absorbent main unit 10, three-dimensional sidegathers 60 and 60 projecting (standing) to the skin side of a wearer areprovided, and gather sheets 62 and 62 forming the three-dimensional sidegathers 60 and 60 are fixed in ranges from the upper both sides of thetop sheet 30 to the inner surfaces of the side flap portions SF.

Details of each part will be described in order below.

(Outer Sheet)

The outer sheet 12 is a sheet constituting the external surface of aproduct. The outer sheet 12 has a shape in which the intermediateportions in the front-back direction LD on the both side portions arenarrowed, and these portions surround the wearer's legs. A nonwovenfabric is suitable for the outer sheet 12, but it is not limitedthereto. The type of the nonwoven fabric is not particularly limited. Asa raw material fiber, for example, in addition to synthetic fibers suchas olefin type such as polyethylene or polypropylene, polyester type,and polyamide type, regenerated fibers such as rayon and cupra, andnatural fibers such as cotton can be used. As a processing method, aspun lace method, a spun bond method, a thermal bond method, an airthrough method, a needle punch method, and the like can be used.However, a long-fiber nonwoven fabric such as a spunbonded nonwovenfabric, an SMS nonwoven fabric, and an SMMS nonwoven fabric ispreferable in that good texture and strength can be compatible. Inaddition to using a single piece of nonwoven fabric, it is also possibleto use multiple nonwoven fabrics in layers. In the latter case, it ispreferable that the nonwoven fabrics are adhered to each other with ahot melt adhesive or the like. When a nonwoven fabric is used, the basisweight of the fiber is desirably 10 to 50 g/m², particularly desirably15 to 30 g/m². The outer sheet 12 can be omitted, and in that case, theliquid impervious sheet 11 can have the same shape as that of the outersheet 12, such that the external surface of a product can be formed.

(Liquid Impervious Sheet)

Although the material of the liquid impervious sheet 11 is notparticularly limited, for example, an olefin resin such as polyethyleneor polypropylene, a laminated nonwoven fabric obtained by stacking anonwoven fabric on a polyethylene sheet or the like, a nonwoven fabricin which liquid permeability is substantially secured through a waterproof film (in this case, a liquid impervious sheet is formed by thewaterproof film and the nonwoven fabric) can be exemplified. Obviously,besides this, in recent years, liquid impervious and moisture permeablematerials which have been favorably used from the standpoint ofprevention of stuffiness can also be exemplified. As a sheet of thisliquid-impervious and moisture-permeable material, for example, amicroporous sheet can be exemplified which is obtained by kneading anolefin resin such as polyethylene resin or polypropylene resin and aninorganic filler, forming a sheet with the kneaded materials andmonoaxially or biaxially stretching the sheet. Further, nonwoven fabricsusing micro denier fibers and a liquid impervious sheet that is notusing a water proof film can also be used as the liquid impervious sheet11. The sheet has liquid impermeability by having high leak proof byreducing air gaps of fibers by heating or applying pressure and byapplying a superabsorbent resin, a hydrophobic resin, or a waterrepellent agent.

(Top Sheet)

As the top sheet 30, a porous or non-porous nonwoven fabric havingliquid permeability can be used. The type of constituent fibers of thenonwoven fabric is not particularly limited. Examples of the constituentfibers can include synthetic fibers such as olefin type such aspolyethylene and polypropylene, polyester type, and polyamide type,regenerated fibers such as rayon and cupra, natural fibers such ascotton, mixed fibers and conjugate fibers in which two or more of theseare used, and the like. Further, the nonwoven fabric may be manufacturedby any processing. Examples of processing methods can include knownmethods such as a spun lace method, a spun bond method, a thermal bondmethod, a melt blown method, a needle punch method, an air throughmethod, and a point bond method. For example, the spun lace method ispreferable when flexibility and drapeability are required, and thethermal bond method is preferable when bulkiness and softness arerequired.

(Intermediate Sheet)

The intermediate sheet 40 is bonded to the back surface of the top sheet30 to promptly move excretion liquid passing through the top sheet 30 tothe side of the absorber 50 and to prevent returning. For bondingbetween the intermediate sheet 40 and the top sheet 30, heat embossingor ultrasonic welding can be used in addition to using a hot meltadhesive. As the intermediate sheet 40, a resin film having a largenumber of through holes can be used in addition to using a nonwovenfabric. As the nonwoven fabric, a material similar to that described inthe section of the top sheet 30 can be used. However, the materialhaving a higher hydrophilicity than that of the top sheet 30 or thematerial having a high fiber density is preferable since those haveexcellent liquid transfer characteristics from the top sheet 30 to theintermediate sheet 40.

Although the intermediate sheet 40 in the illustrated embodiment isshorter than the width of the absorber 50 and disposed at the centerportion, it may be provided over the maximum width. The length of theintermediate sheet 40 in the front-back direction LD may be the same asthe entire length of a diaper, may be the same as the length of theabsorber 50, or may be within a short length range around a regionreceiving a liquid.

(Three-Dimensional Side Gather)

To prevent lateral movement of excrement on the top sheet 30 and toprevent lateral leakage, it is preferable to provide thethree-dimensional side gathers 60 projecting (standing) from the innerfaces on the both sides of a product in the width direction WD.

Each three-dimensional side gather 60 is composed of a gather sheet 62and one or plurality of elongated elastically stretchable members 63fixed to the gather sheet 62 in a stretched state along the front-backdirection LD. As this gather sheet 62, a water repellent nonwoven fabriccan be used, and rubber thread or the like can be used as theelastically stretchable member 63. As illustrated in FIGS. 1 and 3, aplurality of the elastically stretchable members may be provided on eachside, or only one elastically stretchable member may be provided on eachside.

The inner surface of the gather sheet 62 has a fixed start point in thewidth direction WD on the side portion of the top sheet 30. A portionoutside in the width direction WD from this fixed start point is fixedwith a hot melt adhesive or the like to the side portion of the liquidimpervious sheet 11 and the side portion of the outer sheet 12positioned at the outside portion.

In the periphery of the leg, the inside in the width direction WD fromthe fixed start point of each three-dimensional side gather 60 is fixedon the top sheet 30 at both ends of the product in the front-backdirection LD. However, the portion therebetween is a non-fixed freeportion erected by contraction force of one or plurality of theelastically stretchable members 63. Since a diaper is attached to thebody in a boat shape in wearing the diaper, and the contraction force ofone or plurality of the elastically stretchable members 63 acts, thethree-dimensional side gathers 60 erect by the contraction force of oneor plurality of the elastically stretchable members 63 and come in closecontact with the legs. As a result, so-called lateral leakage fromaround the legs is prevented.

Unlike the illustrated embodiment, both end portions in the front-backdirection LD in the portion of the inside in the width direction WD ofeach gather sheet 62 are fixed in a state folded in two having a baseend side portion, which extends inward from a portion outside in thewidth direction WD and a tip side portion, which is folded back on thebody side from the end edge on the center side in the width direction WDof the base end side portion and extending outward in the widthdirection WD, and the portion therebetween may be a non-fixed freeportion.

(Flat Gather)

As illustrated in FIGS. 1 to 3, in each side flap portion SF, on theoutside in the width direction WD in the vicinity of the fixed startpoint of the fixed portion of the gather sheet 62, between the gathersheet 62 and the liquid impervious sheet 11, the elastically stretchablemembers 64, which are made of rubber threads or the like, around the legportions are fixed in a state stretching along the front-back directionLD, whereby the leg portion of each side flap portion SF is formed as aflat gather. The elastically stretchable members 64 around each legportion can also be disposed between the liquid impervious sheet 11 andthe outer sheet 12 in the side flap portion SF. As in the illustratedexample, a plurality of elastically stretchable members 64 around theleg portions may be provided on each side, or only one elasticallystretchable member 64 may be provided on each side.

(Fastening Tape)

As illustrated in FIGS. 1, 2, and 6, each fastening tape 13 includes asheet base material forming a tape attaching portion 13C fixed to theside portion of a diaper and a tape main unit section 13B projectingfrom the tape attaching portion 13C, and an engagement portion 13A withrespect to the ventral side, which is provided in the middle portion inthe width direction WD of the tape main unit section 13B in the seatbase material. A tip end side from the engagement portion 13A is a tabpart. The tape attaching portion 13C of the fastening tape 13 issandwiched between the gather sheet 62 forming an inner layer in theside flap portion and the outer sheet 12 forming an outer layer. Thetape attaching portion 13C is adhered to the both sheets 62 and 12 witha hot melt adhesive. In addition, the engagement portion 13A is bondedto the sheet base material with an adhesive so that it cannot beremoved.

A hook member (male member) of a mechanical fastener (hook and loopfastener) is suitable as the engagement portion 13A. The hook member hasa large number of engagement projections on its external surface side.The engagement projection has a check mark shape, a J shape, a mushroomshape, a T shape, and a double J shape (a shape bonded back to back of aJ shape), but may have any shape. Obviously, an adhesive material layercan also be provided as an engagement portion of the fastening tape 13.

As the sheet base material forming from the tape attaching portion tothe tape main unit section, in addition to various nonwoven fabrics suchas a spunbonded nonwoven fabric, an air-through nonwoven fabric, and aspunlace nonwoven fabric, a plastic film, a polyethylene laminatednonwoven fabric, paper, or a composite material thereof can be used.

(Target Sheet)

It is preferable to provide a target sheet 12T having a target forfacilitating engagement at the engagement portion of each fastening tape13 in the ventral side portion F. In the case where the engagementportion is the hook member 13A, the target sheet 12T can be used havinga large number of loops made of threads to which engagement projectionsof the hook member are tangled are provided on a surface of the sheetbase member made of a plastic film or a nonwoven fabric. Further, in thecase of an adhesive layer, it is possible to use a sheet base materialmade of a plastic film having a smooth surface with high adhesivenessand subjected to a release treatment. In the case where the engagementportion of the fastening tape 13 in the ventral side portion F is madeof a nonwoven fabric, for example, when the outer sheet 12 in theillustrated embodiment is made of a nonwoven fabric, and the engagementportion of the fastening tape 13 is the hook member 13A, the targetsheet 12T may be omitted, and the hook member 13A can be entangled andengaged with the nonwoven fabric of the outer sheet 12. In this case,the target sheet 12T may be provided between the outer sheet 12 and theliquid impervious sheet 11.

(Absorber)

The absorber 50 is a part that absorbs and retains liquid content ofexcrement. The absorber 50 can be adhered to the components on at leastone of the front surface side and back surfaces side via an adhesivesuch as a hot melt adhesive.

As illustrated in the enlarged view of FIG. 7, the absorber 50 is a cellabsorber 50 having the front surface side sheet 51; the back surfaceside sheet 52 disposed on the back surface side of the front surfaceside sheet 51; the cells (small chambers) 55 each of which is surroundedby the bonded portions 54 of the front surface side sheet 51 and theback surface side sheet 52, and in each of which the front surface sidesheet 51 and the back surface side sheet 52 are not bonded; and thesuperabsorbent polymer particles 53 contained in each of the cells 55.In this way, by distributing and retaining the superabsorbent polymerparticles 53 in a large number of the cells 55 each of which issurrounded by the bonded portions 54, the uneven distribution of thesuperabsorbent polymer particles 53 in the absorber 50 can be prevented.The cell absorber 50 can be wrapped with a wrapping sheet (notillustrated). In this case, one wrapping sheet can be wrapped in acylindrical shape so as to surround the absorber on the front and backsurfaces and the both side surfaces of the absorber 50 and two wrappingsheets can be also wrapped so as to sandwich the absorber from both thefront surface side and the back surface side. As the wrapping sheet,tissue paper, particularly crepe paper, a nonwoven fabric, apolyethylene laminated nonwoven fabric, a sheet with small holes, andthe like can be used. However, it is desirable that the wrapping sheetbe a sheet through which the superabsorbent polymer particles do notpass. When a nonwoven fabric is used for the wrapping sheet, ahydrophilic SMS nonwoven fabric (SMS, SSMMS, etc.) is particularlysuitable, and polypropylene and polyethylene/polypropylene compositematerial can be used as a material. The basis weight is preferably 5 to40 g/m², particularly preferably 10 to 30 g/m². When the cell absorber50 is wrapped with the wrapping sheet(s), pulp fibers can be accumulatedon one side of the front surface side and the back surface side of thecell absorber, and the cell absorber together with the pulp fibers canbe wrapped with the wrapping sheet(s) collectively.

The front surface side sheet 51 may be a liquid-pervious material or aliquid impervious material, but preferably it is a liquid-perviousmaterial when it is positioned on the top sheet 30 side as indicated inthe illustrated embodiment. Similarly to the top sheet 30, a porous ornon-porous nonwoven fabric or a porous plastic sheet can be used for thefront surface side sheet 51. In the case of using a nonwoven fabric forthe front surface side sheet 51, examples of the constituent fibersinclude synthetic fibers (including not only single component fibers butalso conjugate fibers) such as olefin type such as polyethylene orpolypropylene, polyester type, and polyamide type, regenerated fiberssuch as rayon and cupra, and natural fibers such as cotton, but it canbe selected without limitation, and it is preferable to use athermoplastic resin fiber because of excellent thermal processability.The fiber bonding method of the nonwoven fabric is not particularlylimited, but to prevent the superabsorbent polymer particles 53 fromfalling off through the sheet, it is preferable to use a bonding methodwhich increases fiber density, such as a spun bond method, a melt blownmethod, and a needle punch method. In the case of using a porous plasticsheet, its pore diameter is preferably smaller than the outer shape ofthe superabsorbent polymer particle 53 to prevent the superabsorbentpolymer particle 53 from falling off through the sheet. When thematerial of the front surface side sheet 51 is hydrophobic, ahydrophilic agent can also be contained.

To facilitate the arrangement of the superabsorbent polymer particles 53in manufacturing and to secure the volume after the swelling upon theabsorption, in the portion forming each cell 55 in the front surfaceside sheet 51, recesses 51 c recessed from the back surface side to thefront surface side are preferably formed, but it may not be formed.

The back surface side sheet 52 may be made of the same material as thefront surface side sheet 51, but in the case where the front surfaceside sheet 51 is composed of a liquid pervious material, a liquidimpervious material can be used for the back surface side sheet 52. Theliquid impervious material usable for the back surface side sheet 52 canbe appropriately selected and used from the materials described in thesection of the liquid impervious sheet 11. Although not illustrated, thefront surface side sheet 51 and the back surface side sheet 52 may beone side layer and another side layer in which one sheet of material isfolded in two.

The superabsorbent polymer particles 53 may not be fixed to the frontsurface side sheet 51 and the back surface side sheet 52, may be freelymovable, and also can be bonded or adhered to the front surface sidesheet 51 and the back surface side sheet 52. Further, the superabsorbentpolymer particles 53 may be agglomerated to some extent.

As the superabsorbent polymer particles 53, those used for this type ofabsorbent articles can be used on an as-is basis. The particle diameterof the superabsorbent polymer particles is not particularly limited, butfor example, when the particles are sieved (shaking for five minutes)using a standard sieve (JIS Z8801-1:2006) of 500 μm and the particlessubjected to sieving with the 500 μm standard sieve are further sieved(shaking for five minutes) using the standard sieve (JIS Z8801-1: 2006)of 180 μm, preferably the proportion of the particles remaining on the500 μm standard sieve is 30% by weight or less, and the proportion ofthe particles remaining on the 180 μm standard sieve is 60% by weight ormore.

The material of the superabsorbent polymer particles 53 can be usedwithout particular limitation, but the material having the waterabsorption capacity of 40 g/g or more is suitable. Examples of thesuperabsorbent polymer particles 53 include starch-based,cellulose-based, and synthetic polymer-based, and starch-acrylic acid(salt) graft copolymers, saponified starch-acrylonitrile copolymers,sodium carboxymethyl cellulose crosslinked products, acrylic acid (salt)polymers, and the like. As the shape of the superabsorbent polymerparticles 53, the shapes of particulate materials which are usually usedare suitable, but other shapes can also be used.

The superabsorbent polymer particles 53 having a water absorption rateof 70 seconds or less, particularly 40 seconds or less, are suitablyused. If the water absorption rate is too slow, back-flow, in which theliquid fed into the absorber 50 returns to the outside of the absorber50, is likely to occur.

The superabsorbent polymer particles 53 having the gel strength of 1,000Pa or more are preferably used. Thereby, even when the absorber 50 isbulky, it is possible to effectively suppress stickiness after liquidabsorption.

The basis weight of the superabsorbent polymer particles 53 can beappropriately determined according to the absorption amount required forthe use of the absorber 50. Therefore, although it cannot be saidunconditionally, the basis weight can be 50 to 350 g/m². When the basisweight of the polymer is less than 50 g/m², it is difficult to securethe absorption amount. When it exceeds 350 g/m², the effect issaturated.

It is desirable that the bonded portion 54 for bonding the front surfaceside sheet 51 and the back surface side sheet 52 be bonded by weldingthe front surface side sheet 51 and the back surface side sheet 52 likeultrasonic welding or heat sealing, but it may be bonded with a hot meltadhesive.

The bonded portions 54 on the front surface side sheet 51 and the backsurface side sheet 52 are provided in dotted line shapes so as to form ahoneycomb shape having the same-sized regular hexagons as unit shapes.As a result, all the cells 55 are the same-sized regular hexagonal cells55 surrounded by the bonded portions 54. The size of each cell 55 can beappropriately determined, and for example, the length 55L of thefront-back direction LD can be about 8 to 30 mm, and the length 55W ofthe width direction WD can be about 10 to 50 mm.

The bonded portions 54 may be formed in a continuous liner shape. In thecase where the bonded portions 54 are formed in a dotted line shape(intermittently), it is desirable that the superabsorbent polymerparticles 53 be not present in the bonded portions 54, but thesuperabsorbent polymer particles may be incorporated therein. In thecase where the bonded portions 54 are formed in a dotted line shape(intermittently), the superabsorbent polymer particles 53 are notpresent between the bonded portions 54 (point interval portion) in thedirection surrounding each of the cells 55 or are supposed to be lessthan those in the cell 55 even if they are present therein.

When the superabsorbent polymer particles 53 in each cell 55 are swollenupon the absorption to fill the inside of the cell 55, if the frontsurface side sheet 51 and the back surface side sheet 52 are stronglybonded at the bonded portions 54 such that the bonded portions 54 arenot peeled off due to the internal pressure, there is a possibility thatthe absorption amount and absorption rate are lowered due to inhibitionby the swelling and so-called gel blocking when the superabsorbentpolymer particles 53 fill in the cell 55. Therefore, the bonded portions54 positioned at least on one side of each cell 55 are formed as weakbonded portions 54 b which can be peeled off by the swelling force ofthe superabsorbent polymer particles 53 in the cell 55 adjacent to thesebonded portions 54, and it is preferable that the cells 55 adjacent tothese bonded portions 54 are coalesced by peeling off of the weak bondedportions 54 b to form a large cell 55. Such a function can be realizedby providing weak bonded portions with decreased bonding strength atappropriate positions and by determining the type and amount of thesuperabsorbent polymer particles 53 disposed in each cell 55 such thatthe volume of the superabsorbent polymer particles 53 in the cell 55upon the saturation absorption, becomes sufficiently larger than thevolume of the cell 55.

Here, comparing with other shapes with the same area, since theperimeter of the regular hexagonal cell 55 is the shortest, in the casewhere the bonded portions 54 surrounding the cell 55 are weak bondedportions 54 b which can be peeled off, when the planar shape of the cell55 is a regular hexagon, the weak bonded portion 54 b can be peeled offwith low swelling force. Therefore, in the case where the bondedportions 54 surrounding the cell 55 are peelable weak bonded portions 54b, when all the cells 55 are formed into the same-sized regular hexagonsby forming the bonded portions 54 into a honeycomb shape, adjacent cells55 are more smoothly and quickly coalesced upon the absorption. Further,if the planar shape of the cell 55 is a regular hexagon, the increase inthe volume of the cell 55 relative to the number of coalesced cells 55is also excellent. Therefore, it is possible to efficiently increase inthe volume of the cell due to coalescence of the cells 55.

All of the bonded portions 54 in the absorber 50 (excluding thoselocated on the outermost side in the width direction) may be weak bondedportions. However, one preferable embodiment is that, as in theembodiments illustrated in FIGS. 7 and 8 to 17, a planar region of theabsorber 50 is divided into the maximum enlargement section 55Gsurrounding a plurality of the cells 55 by the strong bonded portions 54a which are not peeled off due to the swelling force of thesuperabsorbent polymer particles 53 in the adjacent cells 55, and thebonded portions 54 positioned inside each of the maximum enlargementsections 55G is the weak bonded portions 54 b. In this case, all of theweak bonded portions 54 b in the maximum enlargement section 55G arepeeled off due to the swelling pressure upon the absorption of thesuperabsorbent polymer particles 53 in the cells 55, so that a singlecell 55 is formed throughout in the entire maximum enlargement section55G. After that, the strong bonded portions 54 a surrounding the maximumenlargement section 55G are not peeled off due to the swelling pressureupon the absorption of the superabsorbent polymer particles 53 in themaximum enlargement section 55G, such that the gelled superabsorbentpolymer particles 53 swollen upon absorption are hardly to move andcollect to a low place such as a crotch portion, comfort in wearing maynot be hence deteriorated. For example, in the embodiment illustrated inFIG. 8, assuming that urine is excreted at the position of the symbol Z,the urine is diffused to the periphery around the position as indicatedin FIG. 9, and the urine is absorbed in the superabsorbent polymerparticles 53 at each position. At this time, as illustrated in FIGS. 9and 10, as for each the cell 55, in which the swelling pressure of thesuperabsorbent polymer particles 53 inside is increased, the weak bondedportions 54 b surrounding the cell 55 cannot resist against the swellingpressure, and the cell 55 is coalesced with the adjacent cells 55. Thiscoalescence can be continued as long as the weak bonded portions 54 bcan be peeled off due to the swelling upon the absorption of thesuperabsorbent polymer particles 53 and proceeds to reach the cells 55having the strong bonded portions 54 a positioned in their sides. Such afunction is realized, for example, by determining the type and amount ofthe superabsorbent polymer particles 53 disposed in each cell 55 suchthat the volume of the superabsorbent polymer particles 53 in each cell55 upon the saturation absorption, becomes sufficiently larger than thevolume of the each cell 55, and the volume of the superabsorbent polymerparticles 53 in the maximum enlargement section 55G upon the saturationabsorption becomes less than the volume of the coalesced cells in theentire maximum enlargement section 55G surrounded by the strong bondedportions 54 a.

The difference in bonding strength may be easily formed by changing thearea of each of the bonded portions 54 but is not limited thereto. Forexample, in the case of forming the bonded portions 54 with a hot meltadhesive, a method in which the type of the hot melt adhesive is varieddepending on the positions of the cells can be adopted. In the case offorming the bonded portions 54 by welding the front surface side sheet51 and the back surface side sheet 52, the weak bonded portions 54 b canbe formed only by forming the bonded portions 54 into the dotted lineshapes and widening the point interval 54D. However, since the bondedportions 54 can be formed at the boundary between the adjacent cells 55,if the point interval 54D becomes too large, the gaps are increased atthe boundary between the adjacent cells 55, which causes thesuperabsorbent polymer particles 53 to move easily. Therefore, when theweak bonded portions 54 b are formed into the dotted line shape bycombining and arranging the width of the line width 54W of the bondedportions and the width of the point interval 54D, the weak bondedportions 54 b are likely to be peeled off in spite of narrow gaps.

The size of the bonded portion 54 for bonding the front surface sidesheet 51 and the back surface side sheet 52 can be appropriatelydetermined, and for example, the line width (dimension in the directionorthogonal to the direction surrounding the cell 55) 54W can be about0.6 to 8.0 mm. In the case of forming the bonded portions 54 in a dottedline shape (intermittently in the direction surrounding the cells 55),it is preferable that the length 54L of the bonded portion 54 in thedirection surrounding the cell 55 is about 0.6 to 8.0 mm, and the pointinterval 54D is about 0.8 to 10.0 mm. In particular, in the case of thestrong bonded portion 54 a, it is preferable that the line width 54W isabout 1.0 to 4.0 mm, the length 54L of the bonded portion 54 is about1.5 to 4.0 mm, and the point interval 54D is about 0.8 to 2.5 mm.Further, in the case of the weak bonded portion 54 b, it is preferablethat the line width 54W is about 0.6 to 3.5 mm, the length 54L of thebonded portion 54 is about 0.6 to 2.5 mm, and the point interval 54D isabout 1.0 to 4.0 mm.

The width of the bonded portion 54 in the case where the bonded portions54 are formed in a continuous linear shape, and the line width 54W inthe case where the bonded portions 54 are formed in a dotted line shape,are constant in the direction surrounding the cell 55 and also can bechanged. In addition, in the case where the bonded portions 54 areformed in a dotted line shape, the shape of each bonded portion 54 canbe appropriately determined, and all of the bonded portions have thesame shape, or the bonded portions may have different shapes dependingon the site. In particular, when each cell 55 has a polygonal shape, itis preferable to provide the bonded portion 54 at least at one of theintermediate position and each vertex position. Further, in the case ofthe strong bonded portion 54 a, it is preferable to provide it at eachvertex position, but in the case of the weak bonded portion 54 b, it ispreferable not to provide the weak bonded portion 54 b, because the weakbonded portion 54 b can be peeled off easily if not provided at eachvertex position, and the cells 55 are smoothly coalesced. In the casewhere the bonded portion 54 is provided at each vertex position, it isdesirable that the bonded portion 54 have a radial (star) shapeprotruding in the direction of each side.

The size, shape, arrangement (that is, arrangement of the strong bondedportion 54 a) of the maximum enlargement section 55G can beappropriately determined, but if the maximum enlargement section 55G istoo small, it becomes insignificant to provide the strong bondedportions 54 a, and even if a large number of the cells 55 are provided,when the maximum enlargement section is formed to be elongated, afterthe cells 55 are coalesced, the maximum enlargement section becomes tohave a shape in which it is difficult for the cells to be swollen.Therefore, considering that the cell 55 is a regular hexagon, it ispreferable that, as illustrated in FIGS. 11 to 16, in the maximumenlargement section 55G, six or more cells are arranged in two or moredirections, and the peripheral edge of the maximum enlargement sectionforms a closed shape formed by connecting the sides of the cells alongthe peripheral edge thereof while two to four continuous sides areconnected per each cell 55. As a result, the cells 55 can besuccessively coalesced and smoothly enlarged to the maximum enlargementsection 55G, and the maximum enlargement section 55G becomes to beswollen easily. When the cells 55 are enlarged to the maximumenlargement section 55G, the increase in the volume of the cell 55relative to the number of the coalesced cells 55 becomes excellent. InFIGS. 11 to 16, as indicated by reference signs, the strong bondedportions 54 a are represented by bold dotted lines, and the weak bondedportions 54 b are represented by thin dotted lines.

In the peripheral edge of the maximum enlargement section 55G, a partconnecting two consecutive sides per each cell 55 can be a linear part,and a part connecting three consecutive sides per each cell 55 can belinear or a corner portion (turning portion) with an internal angle of120° and a portion connecting four consecutive sides per each cell 55can be a turning portion with an internal angle of 60° or 180°.Therefore, by combining these linear portions and corner portions, theperipheral edge shapes (arrangements of the strong bonded portions 54 a)of the maximum enlargement sections 55G can be formed in substantiallyequilateral triangular shapes as illustrated in FIG. 11, combination ofsubstantially quadrangular shapes and substantially circular shapes asillustrated in FIG. 12, a substantially quadrangular shapes extending inthe entire width direction as illustrated in FIG. 13, substantiallyparallelogram shapes as illustrated in FIGS. 14 and 15, or substantiallyquadrangular shapes as illustrated in FIG. 16.

As illustrated in FIGS. 11 to 14, all of the maximum enlargementsections 55G may satisfy the above conditions, as illustrated in FIG.15, only some of the maximum enlargement sections 55G may satisfy theabove conditions. For example, one of preferred embodiments is that, asillustrated in FIG. 15, honeycomb-shaped bonded portions 54 are formedsuch that the parallel opposite sides of each regular hexagon are alongthe width direction WD, and in the center of the width direction WD ofthe absorber 50, at least one low-swelling-cell row 57, in which all ofthe bonded portions 54 on the both side edges thereof aligned linearlyin the front-back direction are the strong bonded portions 54 a, isprovided, and the both sides in the width direction WD of thelow-swelling-cell row 57 have a higher swellable height than thelow-swelling-cell row 57. The low-swelling-cell row 57 is a row of thecells 55 in which both side edges are comprised of the strong bondedportions 54 a and which are aligned linearly in the front-backdirection, and the low-swelling-cell row 57 is a portion in which themaximum volume of each cell is small and the height can be kept low evenif the inside superabsorbent polymer particles 53 are swollen. When theportions having a higher swellable height than the low-swelling-cell row57 are provided on the both sides in the width direction WD of suchlow-swelling-cell row 57, as illustrated in FIG. 17, a groove having thelow-swelling-cell row 57 as the bottom is formed after absorption, andtherefore the liquid diffusibility in the front-back direction along thegroove improves. A plurality of low-swelling-cell rows 57 can beprovided adjacent to or spaced apart from each other in the widthdirection WD of the absorber 50.

It is preferable that the low-swelling-cell row 57 does not contain thesuperabsorbent polymer particles 53 or contains a smaller amount of thesuperabsorbent polymer 53 per unit area than the cells 55 on the bothsides in the width direction WD of the low-swelling-cell row (forexample, a ratio of the basis weight is ½ or less, especially 1/10 orless). By reducing the amount of the contained superabsorbent polymerparticles 53 in this manner, it is possible to form a liquid diffusiongroove having a low bottom even upon the absorption. In addition, theinside of the low-swelling-cell row 57 does not give a hard texture dueto swelling pressure upon the absorption.

Although the arrangement of the strong bonded portions 54 a is notparticularly limited, for example, as indicated in the illustratedembodiment, if the strong bonded portions 54 a continue throughout acertain range in a specific direction, such as the front-back directionLD, the width direction WD, and the oblique direction, the cells 55 onthe both sides thereof are swollen due to absorption by the internalsuperabsorbent polymer particles 53, the strong bonded portions 54 a arehowever not peeled off to the end. Therefore, after the absorption, thegrooves with the bottom portions of the strong bonded portions 54 a areformed along the specific directions, and the liquid diffusibility inthe directions along the grooves is improved. In addition, if the strongbonded portions 54 a continue in the width direction WD or in theoblique direction, it is possible to prevent the uneven distributionwhich would be caused by the movement of the gelled materials of thesuperabsorbent polymer particles 53 swollen upon the absorption as wellas to improve the liquid diffusibility in the directions. Further, whenthe bonded portions positioned on the outermost side in the widthdirection WD are peeled off, there is a possibility that thesuperabsorbent polymer particles 53 or the gelled superabsorbent polymerparticles 53 leak to the outside of the absorber 50, and therefore it isdesirable that the bonded portions are the strong bonded portions 54 a.From the same viewpoint, it is preferable that the front surface sidesheet 51 and the back surface side sheet 52 are extended to the outsidein the width direction WD to some extent beyond the region where thecells 55 are formed, and the edge bonded portions 54 c are provided inthe extended portions for the reinforcement.

For example, one preferable embodiment is that, as illustrated in FIGS.11 and 14 to 16, the longitudinal-strong-bond lines 58, in each of whichthe strong bonded portions 54 a are continuously aligned in thefront-back direction along the maximum length of the absorber 50, areprovided in the center portion and the both side portions in the widthdirection WD of the absorber 50. A plurality of the lateral-strong-bondlines 59, in each of which the strong bonded portions 54 a are alignedin the width direction WD or the oblique direction from thelongitudinal-strong-bond line 58 in the center portion to each of thelongitudinal-strong-bond lines 58 in the both side portions, is providedat intervals in the front-back direction. In this embodiment, the liquiddiffusibility in the longitudinal direction is improved by thelongitudinal-strong-bond lines 58, and the liquid diffusibility in thelateral direction is improved by the lateral-strong-bond lines 59. Inaddition, the longitudinal-strong-bond lines 58 in the both sideportions also have a function of preventing leakage of thesuperabsorbent polymer particles 53 from the both side edges.

In particular, as illustrated in FIGS. 8 to 11, it is preferable thatthe lateral-strong-bond lines 59 are formed in a zigzag shape extendingin the front-back direction while repeatedly bending left and rightbetween the longitudinal-strong-bond line 58 in the center portion andeach of the longitudinal-strong-bond lines 58 in the both side portions.As a result, the maximum enlargement section 55G having a substantiallytriangular shape with one of the vertexes positioned in thelongitudinal-strong-bond line 58 in the center portion and the maximumenlargement section 55G having a substantially triangular shape with oneof the vertexes positioned in each of the longitudinal-strong-bond lines58 on the both side portions are repeatedly formed alternately in thefront-back direction. When the lateral-strong-bond lines 59 are formedin the zigzag shape as described above, it is preferable because theliquid diffusion in the lateral direction can be efficiently facilitatedwith the small number of the lateral-strong-bond lines 59, and themaximum enlargement section 55G has a substantially triangular shapewhich is easily swollen, and the increase in the volume of the cells 55relative to the number of the coalesced cells 55 is excellent.

As illustrated in FIG. 13, it is also possible to omit thelongitudinal-strong-bond line 58 in the center portion and only providethe lateral-strong-bond lines 59. Further, as illustrated in FIG. 13, itis possible to form the honeycomb-shaped bonded portions 54 such thatthe parallel opposite sides of the regular hexagons are along thefront-back direction LD. Although not illustrated, it is also possibleto form the honeycomb-shaped bonded portions 54 such that the parallelopposite sides of the regular hexagons are along the oblique direction.

The number of the longitudinal-strong-bond lines 58 and the number ofthe lateral-strong-bond lines 59 may be suitably determined, but threeto four longitudinal-strong-bond-lines 58 are preferably provided whenthe longitudinal-strong-bond line is provided along the side edge of thecells 55 positioned on the outermost side of the absorber in the widthdirection WD, and one to two longitudinal-strong-bond lines 58 areprovided when the longitudinal-strong-bond line is not provided alongthe side edge. It is desirable that the number of thelateral-strong-bond lines 59 be about four to ten.

As illustrated in FIG. 8, it is also possible to provide the empty cells56 which do not contain the superabsorbent polymer particles 53 or whichcontain a smaller amount of the superabsorbent polymer particles 53 thanother cells even if the cells contain them. In FIG. 8, an area 53Ahaving a pattern of hatched lines indicates a region for containing thesuperabsorbent polymer particles 53. Since this region is based onassumption of the shape of a region in which the superabsorbent polymerparticles 53 are dispersed in the manufacturing, there are portionswhich are not covered by the pattern of the hatched lines in the cells55 in the peripheral edge. Actually, in the case where thesuperabsorbent polymer particles 53 can move in each cell 55, thepositions of the superabsorbent polymer particles 53 in the cell 55 arenot fixed in a state of the product, and the superabsorbent polymerparticles 53 can be distributed throughout the cells 55 in the samemanner as in the state illustrated in FIG. 7. The amount of thesuperabsorbent polymer particles 53 contained in the empty cell 56 ispreferably ½ or less, particularly 1/10 or less, of the other cells interms of weight ratio, and it is particularly preferable that thesuperabsorbent polymer particles 53 are not contained at all in theempty cell. For example, since the front end and the back end of theabsorber 50 are formed by cutting into the individual absorbers 50 inthe manufacturing, if the superabsorbent polymer particles 53 arecontained in portions where the cutting is performed, the life of ablade of a cutting device may be shortened. Therefore, it is desirablethat at least the cells 55 located at the positions through which thefront and back ends of the absorber 50 pass be the empty cells 56.Further, in the absorber 50 obtained by mixing superabsorbent polymerparticles 53 with a hydrophilic short fiber such as fluff pulp, andbeing accumulated in a cotton form, generally, the intermediate portionin the front-back direction LD is formed in a narrow shape so as to bealong the legs. However, also in the absorber 50, by setting, the cells55 on the both sides in the intermediate portion in the front-backdirection LD, as the empty cells 56, the intermediate portion in thefront-back direction LD will be less swollen even after absorption, andtherefore, the absorber 50 has a shape that fits around the legs evenafter the absorption.

In the case of manufacturing the absorber 50, since it is difficult toaccurately distribute a predetermined amount of the superabsorbentpolymer particles 53 to the individual cells 55, it is preferable thatthe superabsorbent polymer particles 53 are uniformly dispersedthroughout the entire region for containing the superabsorbent polymerparticles 53 (the region excluding the portions to be the empty cells56) on the front surface side sheet 51 or the back surface side sheet52, and then the bonded portions 54 are formed to bond the front surfaceside sheet 51 and the back surface side sheet 52 as one unit and toconfine the superabsorbent polymer particles 53 in each cell 55. In thiscase, particularly with respect to the peripheral cells 55 positioned inthe peripheral edge of the region for containing the superabsorbentpolymer particles 53, it is difficult to disperse the superabsorbentpolymer particles 53 in an accurate shape matching with the peripheraledge of the cells 55. Therefore, as can be seen from the shape of thedispersing region 53A which is defined for dispersing the superabsorbentpolymer particles 53 and indicated by the pattern of hatched lines inFIG. 8, it is desirable to disperse the superabsorbent polymer particles53 such that the peripheral edge of the region 53A for the dispersionpasses through the middle of the peripheral cells 55. In this case, theamount of the superabsorbent polymer particles 53 contained in theperipheral cells 55 is less than the amount of the same contained in thecells 55 positioned inside the peripheral cells 55, and in the casewhere the cells 55 are further provided outside the peripheral cells 55,these outer cells 55 become the empty cells 56 which do notsubstantially contain the superabsorbent polymer particles 53.

In the above example, only the superabsorbent polymer particles 53 arecontained in the cells 55, but it is also possible to contain thesuperabsorbent polymer particles 53 together with particulate materialsother than the superabsorbent polymer particles 53, such as deodorantparticles.

Explanation of Terms Used Herein

In the case where the following terms are used in the specification,those have the following meanings unless otherwise specified in thespecification.

“Machine direction (MD)” and “cross direction (CD)” mean the flowdirection (MD) in a manufacturing facility and the lateral direction(CD) orthogonal to the flow direction, and either one is the front-backdirection of a product, and the other is the width direction of theproduct. The MD of a nonwoven fabric is the direction of fiberorientation of the nonwoven fabric. “Fiber orientation” is a directionalong which a fiber of a nonwoven fabric runs and determined by, forexample, a measurement method in accordance with the fiber orientationtest method based on the zero span tensile strength of TAPPI T481 and asimple measurement method for determining the direction of fiberorientation from the ratio of the tensile strength in the front-backdirection to the width direction.

“Spread state” means a flatly spread state without contraction or slack.

“Stretch rate” means the value when the natural length is taken as 100%.

“Artificial urine” is prepared by mixing urea: 2 wt %, sodium chloride:0.8 wt %, calcium chloride dihydrate: 0.03 wt %, magnesium sulfateheptahydrate: 0.08 wt %, and ion exchanged water: 97.09 wt %, and thoseare used at a temperature of 40° C. unless otherwise specified.

“Gel strength” is measured as follows: 1.0 g of superabsorbent polymerare added to 49.0 g of artificial urine and the mixture is stirred witha stirrer. The resulting gel is left for three hours in athermohygrostat bath at 40° C., 60% RH and then cooled to roomtemperature. The gel strength of the gel is measured with Curdmeter (MAXME-500, manufactured by I. Techno Engineering Co., Ltd).

“Basis weight” is measured as follows. After the sample or test piece ispreliminary dried, it is allowed to stand in a test room or apparatusunder normal conditions (the test location is at a temperature: 20±5°C., relative humidity: 65% or less) until the constant mass. Thepreliminary drying is to make the sample or test piece be constant massin an environment within a relative humidity of 10 to 25% and atemperature not exceeding 50° C. The fibers of an official moistureregain of 0.0% does not need preliminary drying. A cut sample with asize of 200 mm by 250 mm (±2 mm) is cut from a test piece in theconstant mass, with a cutting template (200 mm×250 mm, ±2 mm). Thesample is weighed and the weight is multiplied by 20 into the weight perone square meter. The resulting value is defined as the basis weight.

“Thickness” is automatically measured under the conditions of a load of10 gf/cm² in a pressurized area of 2 cm² using an automatic thicknessmeasuring device (KES-G5 handy compression tester).

“Water absorption capacity” is measured according to JIS K7223-1996“Testing method for water absorption capacity of super absorbentpolymers”.

“Water absorption rate” is the “time that elapses before the end point”measured in accordance with JIS K7224-1996 “Testing method for waterabsorption rate of super absorbent polymers” has been carried out using2 g of superabsorbent polymer and 50 g of physiological saline solution.

When environmental conditions in tests and measurements are notdescribed, the tests and measurements shall be carried out in a testroom or apparatus under normal conditions (the test location is at atemperature: 20±5° C., relative humidity: 65% or less).

The dimension of each part means the dimension in the spread state, notthe natural length state, unless otherwise stated.

REFERENCE SIGNS LIST

-   -   11 liquid impervious sheet    -   12 outer sheet    -   12T target sheet    -   13 fastening tape    -   13A engagement portion    -   13B tape main unit section    -   13C tape attachment portion    -   30 top sheet    -   40 intermediate sheet    -   60 three-dimensional side gather    -   62 gather sheet    -   50 absorber    -   51 front surface side sheet    -   51 c recess    -   52 back surface side sheet    -   53 superabsorbent polymer particles    -   54 bonded portion    -   54 a strong bonded portion    -   54 b weak bonded portion    -   54 c edge bonded portion    -   55 cell    -   55G maximum enlargement section    -   WD width direction    -   56 empty cell    -   57 low-swelling-cell row    -   58 longitudinal-strong-bond line    -   59 lateral-strong-bond line

1. An absorbent article comprising an absorber including: a frontsurface side sheet; a back surface side sheet disposed on the backsurface side of the front surface side sheet; a plurality of cells eachof which is surrounded by bonded portions of the front surface sidesheet and the back surface side sheet, and inside each of which thefront surface side sheet and the back surface side sheet are not bonded;and particulate materials which include superabsorbent polymer particlesand which are contained in the cells, wherein the bonded portions areprovided in continuous line shapes or dotted line shapes so as to form ahoneycomb shape having the same-sized regular hexagons as unit shapes,all the cells are the same-sized regular hexagonal cells each of whichis surrounded by the bonded portions, and the bonded portions positionedon at least one side of each cell are weak bonded portions which can bepeeled off due to a swelling force of the superabsorbent polymerparticles in the cells adjacent to the bonded portions.
 2. The absorbentarticle according to claim 1, comprising a plurality of the maximumenlargement sections in each of which a portion composed of six or morecells aligned in two or more directions is surrounded by strong bondedportions which are not peeled off against the swelling force of thesuperabsorbent polymer particles in the adjacent cells, wherein thebonded portions positioned inside the strong bonded portions in themaximum enlargement sections, are the weak bonded portions, andperipheral edge shapes of the maximum enlargement sections are closedshapes formed by connecting two to four continuous sides per each cellin cells along the peripheral edges of the maximum enlargement sections.3. The absorbent article according to claim 1, whereinlongitudinal-strong-bond lines on which the strong bonded portions arecontinuously provided in the front-back direction along the maximumlength of the absorber, are provided in the center portion and the bothside portions in the width direction of the absorber, respectively aplurality of lateral-strong-bond lines on which the strong bondedportions are provided continuously in the width direction or the obliquedirection from the longitudinal-strong-bond line in the center portionto each of the longitudinal-strong-bond lines in the both side portionsis provided at intervals in the front-back direction, and sections,which are surrounded by the longitudinal-strong-bond lines and thelateral-strong-bond lines so as to be partitioned, are the maximumenlargement sections in which the bonded portions positioned betweencells in the sections are only the weak bonded portions.
 4. Theabsorbent article according to claim 3, wherein the lateral-strong-bondlines are formed in a zigzag shape extending in the front-back directionwhile repeatedly bending left and right between thelongitudinal-strong-bond line in the center portion and each of thelongitudinal-strong-bond lines in the both side portions.
 5. Theabsorbent article according to claim 1, wherein the bonded portions arearranged such that the parallel opposite sides of the regular hexagonsformed in the honeycomb-shaped bonded portions are along the widthdirection, at least one low-swelling-cell row in which all of the bondedportions on the both side edges thereof aligned linearly in thefront-back direction are the strong bonded portions is provided in thecenter in the width direction of the absorber, and the both sides in thewidth direction of the low-swelling-cell row, have a higher swellableheight than the low-swelling-cell row.
 6. The absorbent articleaccording to claim 5, wherein the low-swelling-cell row does not containa superabsorbent polymer particle or contains a smaller amount of thesuperabsorbent polymer particles per unit area than the cells on theboth sides in the width direction of the low-swelling-cell row.
 7. Theabsorbent article according to claim 2, wherein the bonded portions areportions at which the front surface side sheet and the back surface sidesheet are welded, the weak bonded portions and the strong bondedportions are provided in dotted line patterns, the line width of theweak bonded portions is narrower than the line width of the strongbonded portions, and the point interval of the weak bonded portions iswider than the point interval of the strong bonded portions.
 8. Theabsorbent article according to claim 1, wherein the bonded portion isnot provided at positions where the sides on which the weak bondedportions are positioned intersect with each other in the cells.
 9. Theabsorbent article according to claim 1, wherein at least cells arrangedat positions through which the front and back ends of the absorber passand cells in the both side portions in an intermediate portion of thefront-back direction of the absorber are empty cells which do notcontain a superabsorbent polymer particle or which contains a smalleramount of the superabsorbent polymer particles per unit area than othercells.
 10. The absorbent article according to claim 2, whereinlongitudinal-strong-bond lines on which the strong bonded portions arecontinuously provided in the front-back direction along the maximumlength of the absorber, are provided in the center portion and the bothside portions in the width direction of the absorber, respectively aplurality of lateral-strong-bond lines on which the strong bondedportions are provided continuously in the width direction or the obliquedirection from the longitudinal-strong-bond line in the center portionto each of the longitudinal-strong-bond lines in the both side portionsis provided at intervals in the front-back direction, and sections,which are surrounded by the longitudinal-strong-bond lines and thelateral-strong-bond lines so as to be partitioned, are the maximumenlargement sections in which the bonded portions positioned betweencells in the sections are only the weak bonded portions.
 11. Theabsorbent article according to claim 2, wherein the bonded portions arearranged such that the parallel opposite sides of the regular hexagonsformed in the honeycomb-shaped bonded portions are along the widthdirection, at least one low-swelling-cell row in which all of the bondedportions on the both side edges thereof aligned linearly in thefront-back direction are the strong bonded portions is provided in thecenter in the width direction of the absorber, and the both sides in thewidth direction of the low-swelling-cell row, have a higher swellableheight than the low-swelling-cell row.
 12. The absorbent articleaccording to claim 3, wherein the bonded portions are arranged such thatthe parallel opposite sides of the regular hexagons formed in thehoneycomb-shaped bonded portions are along the width direction, at leastone low-swelling-cell row in which all of the bonded portions on theboth side edges thereof aligned linearly in the front-back direction arethe strong bonded portions is provided in the center in the widthdirection of the absorber, and the both sides in the width direction ofthe low-swelling-cell row, have a higher swellable height than thelow-swelling-cell row.
 13. The absorbent article according to claim 4,wherein the bonded portions are arranged such that the parallel oppositesides of the regular hexagons formed in the honeycomb-shaped bondedportions are along the width direction, at least one low-swelling-cellrow in which all of the bonded portions on the both side edges thereofaligned linearly in the front-back direction are the strong bondedportions is provided in the center in the width direction of theabsorber, and the both sides in the width direction of thelow-swelling-cell row, have a higher swellable height than thelow-swelling-cell row.
 14. The absorbent article according to claim 7,wherein the bonded portion is not provided at positions where the sideson which the weak bonded portions are positioned intersect with eachother in the cells.